The type of accent and expressions you are taught as a learner are always using the Tokyo Dialect. This is what all newsreaders, announcers and professionals use. Generally, every Japanese person can speak using this dialect, but depending on where they come from in Japan they might have an additional dialect that use.
Unless you have experience living in Japan, particularly in a city where there is a different dialect/accent spoken it's very difficult as a learner for you to pick up. It's ever difficult for native Japanese speakers to understand the different dialects. If you're from Hiroshima and you're talking to someone from Hokkaido and you are both using your dialects, there is a chance every now and then during the conversation you might not fully understand what the other person has said to you. The Tokyo dialect the middle ground, that everyone can understand.
I used to live in Kansai and they have a different accent and dialect there. It was very difficult for me to understand at first, but I soon got used to it, and being a foreigner MOST people would switch to using the Tokyo dialect when speaking to me.
To give you an idea Tokyo Dialect on the left, Kansai on the right
Wakarimasen わかりません→わからへん Wakarahen
Honto 本当→ほんま Honma
It's exactly the same as the different cities in England all having different accents and expressions. Or the different states in America. If you hear a southern accent in America, you can expect at some point that person might say "Y'all" while you're talking to them.